A hand played in such a way that you would not suspect it of being very good,
but that turns out to be so.
For example, if, in lowball, two players kept raising each other back and
forth, and a third just kept calling
all the bets, you might suspect that he was drawing one to a good hand. If
he turned out to have a pat wheel,
that would be a concealed hand. In any poker game, if one player lets the
others do all the betting for him, usually
because the situation allows him to just keep calling without ever having
to make a raise or leading bet of his own,
and that player actually holds a hand that cannot lose, he is said to have
a concealed hand. Also called hidden hand.